MPG Average Tanking

Okay, maybe someone can help me understand what the hell happened to my MPG Average.

So here's what's up, I reprogrammed my truck using the AEV ProCal a week ago this past Monday. It's correct within 1 MPH for the tire size on my truck. Before the program I was averaging 12.3-12.7 MPG. After finally getting everything programmed correctly I was averaging 13.4-13.7 MPG.

On Sunday I sat in my truck at idle for about 30-45 min performing the software update to my 8.4 radio. At the start of idle I was at 13.5 MPG and it dropped to 13.1 MPG. Weird since I wasn't driving.

Since then I've been between 12.6 and 12.9 MPG. I'm not putting my foot into the hemi. My driving habits have not changed. But there are times where I'll still lose .1 MPG at idle.

I don't get it... And for the record, I didn't buy the truck for good MPG. I know a 6.4 won't make amazing gas mileage. But that's a loss of 1 MPG just outta nowhere.

Thoughts??

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Cold temp or fuel blend change

Can't attest to the loss of mileage during driving, likely just the truck getting used to the tune, but as far as the idling goes its just because you're burning fuel while idling and not actually traveling any distance. For example you could burn a whole gallon of gas idling and travel 0 miles so you are getting 0 mpg for a whole gallon, effecting your average. My MPG is always about 1-2mpg lower in the winter because I let my truck idle for awhile.

YUP!

Yeah, I know it burns fuel at idle. Just didn't think that would calculate into the MPG Average. Figured that was driven numbers only.

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Idle time kills average MPG! My work car is a Kia Forte and it eeeeeeasily gets 35-40 mpg on the highway and will hold 25-30 mpg in city driving. It idles A LOT on jobs and accordingly, my average is 20 mpg. If I do a hard reset on the average mpg on Monday, it will start high and ever so slowly go to crap by Friday and be back to 20 mpg.

Mine drops bad when
I idle a lot.

Odin said:

Yeah, I know it burns fuel at idle. Just didn't think that would calculate into the MPG Average. Figured that was driven numbers only.

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Click to expand...

It does

I live in the city and I average 12.8 to 13.1 but if I ever hop on the interstate I shoot right back up

Yep, when I start using remote start in the Fall, MPG goes right out the window and I don't even look at it anymore LOL.

When I did my AEV programming I think the computers starting reading slightly lower MPG, but it's probably because it is now actually more accurately compensating for the tires.

i idle a ton and it is 100% integrated into the formula.

stock 2018 powerwagon on stock wheels and tires and no matter how many times or when i reset the MPG guage it would end up back at 10-10.5 MPG over the course of a few days.

adding the 35 TOYO and 17inch methods (112LBS each corner) if i drive and idle the same i always do i will get 9.5- 9.8MPG

BUT i notice i can average better mileage on highway at speed with the toyos...less rolling resistance at the same PSI?

Why would idle be any different than stop and go driving. Engine is running, but you are not covering a lot of miles, so miles divided by gallons consumed renders an average that SUCKS!

As far as bad mileage after idle, combustion at idle (unloaded) is pretty crappy, so you may have some carbon fouling.

Seafaom treatment via the intake may bring back your va-va-va-room.

Odin said:

Yeah, I know it burns fuel at idle. Just didn't think that would calculate into the MPG Average. Figured that was driven numbers only.

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Click to expand...

No it calculated idle as well


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